Before any “domestic” test, make sure the hood has been installed correctly following the installation steps contained in the instructions manual supplied with the product. This said, an “approximate” test can be performed by switching the hood on parallel to the cooker on which you can boil some water. If the installation is correct and poor extraction is caused by a fault in the product, you must call the Faber-authorised Technical Assistance Centre (for info: https://www.faberspa.com/en/post-sales-assistance/) providing the codes written on the label inside the hood.
Alternatively, you can open an assistance request by calling on 199.509.509 and providing the information on the hood.